Automatic call ring back is a feature of conventional phone systems, but it only relates to voice communications and does not take into account the potentially shifting capabilities of both users involved. A user who wishes to reach another user and finds them busy after attempting a call in a phone system may enter a special code that tells the central office to watch the called party. The calling party then hangs up. When the called party is no longer on the phone, the central office automatically rings the original calling party and completes the call when the calling party picks up the handset.
Modern communication systems have a large number of capabilities including integration of various communication modalities with different services. For example, instant messaging, voice/video communications, data/application sharing, white-boarding, and other forms of communication may be combined with presence and availability information of subscribers. Such systems may provide subscribers with the enhanced capabilities such as providing instructions to callers for various status categories, alternate contacts, calendar information, and comparable features.
When a subscriber of an enhanced communication system with above described capabilities wishes to enter into a multimodal communication session with another party, the other party may not be available for one or more of the modalities or not have the capability to accommodate one or more of the requested modalities at all. Furthermore, the party being contacted may not realize that they have someone waiting to contact them.